閱讀以下說明和 Java 程序，填補代碼中的空缺，將解答填入答題紙的對應(yīng)欄內(nèi)。
【說明】
以下 Jave 代碼實現(xiàn)一個簡單客戶關(guān)系管理系統(tǒng)（CrM）中通過工廠（Customerrfactory ）對象來創(chuàng)建客戶（Customer）對象的功能?？蛻舴譃閯?chuàng)建成功的客戶（realCustomer）和空客戶（NullCustomer）。空客戶對象是當(dāng)不滿足特定條件時創(chuàng)建或獲取的對象。類間關(guān)系如圖 5-1 所示。

【Java 代碼】
Abstract class Customer﹛
Protected String name;
( )boolean isNil( )
( )String getName( );
﹜

Class realCustomer ( )Customer﹛
Public realCustomer（String name ）﹛ return false; ﹜
﹜

Class NullCustomer( )Customer﹛
Public String getName( )﹛ return ″Not Available in Customer Database″; ﹜
Public boolean isNil( )﹛ return true; ﹜
﹜

class Customerfactory {
public String[] names = {"rob"，"Joe"，"Julie"};
public Customer getCustomer（String name） {
for （int i = 0; i < names.length;i++） {
if （names[i].( )）﹛
return new realCusωmer（name）;
﹜
﹜
return ( )
﹜
﹜

Public class CrM﹛
Public viod get Customer( )﹛
Customerfactory( )
Customer customer1-cf.getCustomer（″rob″）;
Customer customer2=cf.getCustomer（″rob″）;
Customer customer3= cf.getCustomer（″Julie″）;
Customer customer4= cf.getCustomer（″Laura″）;
System.out.println（″customer1.getName( )）;
System.out.println（″customer2getName( )）;
System.out.println（″customer3.getName( )）;
System.out.println（″customer4.getName( )）;
﹜

Public static viod main （String[]arge）﹛
CrM crm =new CrM( );
Crm,getCustomer( );
﹜
﹜
／*程序輸出為：
Customer
rob
Not Available in Customer Database
Julie
Not Available in Customer Datable
*／
int main( )﹛
CrM*crs=newCrM( );
Crs->getCustomer( );
Crs->getCustomer( );
Delete crs;
return( );
﹜
／*程序輸出為：
Customer
rob
Not Available ini Customer Database
Julie
Not Available in Customer Database